The invention relates to nail plates of the type used in building construction to protect electric wiring and like service lines against accidental damage.
More particularly, after the basic framework is assembled, for example a stud wall or a block wall, the electrical wiring is run along the surface thereof. In a conventional wood stud wall, this will normally entail a notching or recessing of the face edges of the studs for a recessed positioning of the wire therein. In order to protect the notch-received wire it is a common expedient to overlay each notch with a flat metal plate which is secured to the corresponding stud both above and below the notch, preferably by integral teeth or prongs struck from the plate. Thus, an effective protective means is provided against an accidental piercing of the wire by nails or the like as the wall-finishing panels are mounted. Similarly, the nail plates will effectively protect the wire against accidental damage by driven fasteners under a variety of other circumstances such as the wall-mounting of shelving, decorative or utilitarian articles, and the like.
An example of a conventional nail plate is illustrated in U.S. Pat. No. 3,280,869, J. C. Juriet, issued Mar. 15, 1966. This patent is of particular interest in detailing the need for and advantages derived from such nail plates.
The conventional nail plate, in addition to being used in conjunction with wood stud walls as the Juriet patent also is used on furred walls for similarly protecting electric wiring or the like. Such walls, normally formed of concrete block or poured concrete, have a series of thin wooden strips, furring strips, nailed thereto to provide a nailing base for wall-finishing panels and the like. The furring strips will normally include at least one horizontal base or sill strip with multiple vertical strips thereabove and at predetermined spacing, normally 16" in a conventional wall. The horizontal strip includes a continuous upper support edge or ledge extending laterally inward from the forward nailing surface. The vertical strips, at the lower ends thereof, are spaced slightly above the upper edge of the sill strip. In the conventional arrangement, a planar nail plate is nailed to the lower portion of each vertical strip and the horizontal strip therebelow to span the gap or recess therebetween and provide a barrier protecting the wire against any accidental penetration by a nail. This juncture point, as with the notches in the studs of Juriet, is particularly vulnerable in that surface paneling and the like is conventionally nailed along the vertical nailing surfaces, whether this be studs or furring strips.
In addition to the conventional nailing plate, in a furred wall it is necessary and in many instances required by building codes to specifically provide hold-down means to stabilize the wire on the narrow upper edge of the horizontal furring strip to avoid any tendency for the wire to shift. Such a hold-down is conventionally effected by using driven staples which span the wire and penetrate the strip to the opposite sides thereof. While the combination of the nail plates and staples effectively protects and retains the wiring, there is a substantial expenditure of labor in nailing both the nail plates and the staples, in addition to the problems of effectively driving the staples immediately adjacent the wall and into the narrow upper edge of the strip. A substantially greater problem is the tendency for the furring strips themselves to come loose from the wall when subjected to the combined forces required to both mount the nail plates and drive the staples. In other words, under actual working conditions, the wire is run, the nail plates nailed in position and the staples driven. The driving of the staples has a tendency to cause the nails mounting the furring strips to loosen within the block wall. This in turn requires a renailing of the furring strips either by the electrician installing the wiring or by the original installers of the furring strips. In either case, there is an undesireable and expensive waste of labor and time.